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Properties

Label 400c1
Conductor $400$
Discriminant $-5120000$
j-invariant \( -\frac{25}{2} \)
CM no
Rank $1$
Torsion structure trivial

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Minimal Weierstrass equation

Minimal Weierstrass equation

Simplified equation

\(y^2=x^3-x^2-8x+112\) Copy content Toggle raw display (homogenize, simplify)
\(y^2z=x^3-x^2z-8xz^2+112z^3\) Copy content Toggle raw display (dehomogenize, simplify)
\(y^2=x^3-675x+79650\) Copy content Toggle raw display (homogenize, minimize)

Copy content comment:Define the curve
 
Copy content sage:E = EllipticCurve([0, -1, 0, -8, 112])
 
Copy content gp:E = ellinit([0, -1, 0, -8, 112])
 
Copy content magma:E := EllipticCurve([0, -1, 0, -8, 112]);
 
Copy content oscar:E = elliptic_curve([0, -1, 0, -8, 112])
 
Copy content comment:Simplified equation
 
Copy content sage:E.short_weierstrass_model()
 
Copy content magma:WeierstrassModel(E);
 
Copy content oscar:short_weierstrass_model(E)
 

Mordell-Weil group structure

\(\Z\)

Copy content comment:Mordell-Weil group
 
Copy content magma:MordellWeilGroup(E);
 

Mordell-Weil generators

$P$$\hat{h}(P)$Order
$(12, 40)$$0.064899209853980867519354340036$$\infty$

Integral points

\((-4,\pm 8)\), \((-3,\pm 10)\), \((2,\pm 10)\), \((12,\pm 40)\), \((18,\pm 74)\), \((332,\pm 6040)\) Copy content Toggle raw display

Copy content comment:Integral points
 
Copy content sage:E.integral_points()
 
Copy content magma:IntegralPoints(E);
 

Invariants

Conductor: $N$  =  \( 400 \) = $2^{4} \cdot 5^{2}$
Copy content comment:Conductor
 
Copy content sage:E.conductor().factor()
 
Copy content gp:ellglobalred(E)[1]
 
Copy content magma:Conductor(E);
 
Copy content oscar:conductor(E)
 
Discriminant: $\Delta$  =  $-5120000$ = $-1 \cdot 2^{13} \cdot 5^{4} $
Copy content comment:Discriminant
 
Copy content sage:E.discriminant().factor()
 
Copy content gp:E.disc
 
Copy content magma:Discriminant(E);
 
Copy content oscar:discriminant(E)
 
j-invariant: $j$  =  \( -\frac{25}{2} \) = $-1 \cdot 2^{-1} \cdot 5^{2}$
Copy content comment:j-invariant
 
Copy content sage:E.j_invariant().factor()
 
Copy content gp:E.j
 
Copy content magma:jInvariant(E);
 
Copy content oscar:j_invariant(E)
 
Endomorphism ring: $\mathrm{End}(E)$ = $\Z$
Geometric endomorphism ring: $\mathrm{End}(E_{\overline{\Q}})$  =  \(\Z\)    (no potential complex multiplication)
Copy content comment:Potential complex multiplication
 
Copy content sage:E.has_cm()
 
Copy content magma:HasComplexMultiplication(E);
 
Sato-Tate group: $\mathrm{ST}(E)$ = $\mathrm{SU}(2)$
Faltings height: $h_{\mathrm{Faltings}}$ ≈ $-0.032952415583936223336593258536$
Copy content comment:Faltings height
 
Copy content gp:ellheight(E)
 
Copy content magma:FaltingsHeight(E);
 
Copy content oscar:faltings_height(E)
 
Stable Faltings height: $h_{\mathrm{stable}}$ ≈ $-1.2625789002885816576207451577$
Copy content comment:Stable Faltings height
 
Copy content magma:StableFaltingsHeight(E);
 
Copy content oscar:stable_faltings_height(E)
 
$abc$ quality: $Q$ ≈ $1.0904350906962674$
Szpiro ratio: $\sigma_{m}$ ≈ $3.823871863737538$

BSD invariants

Analytic rank: $r_{\mathrm{an}}$ = $ 1$
Copy content comment:Analytic rank
 
Copy content sage:E.analytic_rank()
 
Copy content gp:ellanalyticrank(E)
 
Copy content magma:AnalyticRank(E);
 
Mordell-Weil rank: $r$ = $ 1$
Copy content comment:Mordell-Weil rank
 
Copy content sage:E.rank()
 
Copy content gp:[lower,upper] = ellrank(E)
 
Copy content magma:Rank(E);
 
Regulator: $\mathrm{Reg}(E/\Q)$ ≈ $0.064899209853980867519354340036$
Copy content comment:Regulator
 
Copy content sage:E.regulator()
 
Copy content gp:G = E.gen \\ if available matdet(ellheightmatrix(E,G))
 
Copy content magma:Regulator(E);
 
Real period: $\Omega$ ≈ $1.9969667382808496307794292130$
Copy content comment:Real Period
 
Copy content sage:E.period_lattice().omega()
 
Copy content gp:if(E.disc>0,2,1)*E.omega[1]
 
Copy content magma:(Discriminant(E) gt 0 select 2 else 1) * RealPeriod(E);
 
Tamagawa product: $\prod_{p}c_p$ = $ 12 $  = $ 2^{2}\cdot3 $
Copy content comment:Tamagawa numbers
 
Copy content sage:E.tamagawa_numbers()
 
Copy content gp:gr=ellglobalred(E); [[gr[4][i,1],gr[5][i][4]] | i<-[1..#gr[4][,1]]]
 
Copy content magma:TamagawaNumbers(E);
 
Copy content oscar:tamagawa_numbers(E)
 
Torsion order: $\#E(\Q)_{\mathrm{tor}}$ = $1$
Copy content comment:Torsion order
 
Copy content sage:E.torsion_order()
 
Copy content gp:elltors(E)[1]
 
Copy content magma:Order(TorsionSubgroup(E));
 
Copy content oscar:prod(torsion_structure(E)[1])
 
Special value: $ L'(E,1)$ ≈ $1.5552187610293025813988289082 $
Copy content comment:Special L-value
 
Copy content sage:r = E.rank(); E.lseries().dokchitser().derivative(1,r)/r.factorial()
 
Copy content gp:[r,L1r] = ellanalyticrank(E); L1r/r!
 
Copy content magma:Lr1 where r,Lr1 := AnalyticRank(E: Precision:=12);
 
Analytic order of Ш: Ш${}_{\mathrm{an}}$  ≈  $1$    (rounded)
Copy content comment:Order of Sha
 
Copy content sage:E.sha().an_numerical()
 
Copy content magma:MordellWeilShaInformation(E);
 

BSD formula

$$\begin{aligned} 1.555218761 \approx L'(E,1) & = \frac{\# ะจ(E/\Q)\cdot \Omega_E \cdot \mathrm{Reg}(E/\Q) \cdot \prod_p c_p}{\#E(\Q)_{\rm tor}^2} \\ & \approx \frac{1 \cdot 1.996967 \cdot 0.064899 \cdot 12}{1^2} \\ & \approx 1.555218761\end{aligned}$$

Copy content comment:BSD formula
 
Copy content sage:# self-contained SageMath code snippet for the BSD formula (checks rank, computes analytic sha) E = EllipticCurve([0, -1, 0, -8, 112]); r = E.rank(); ar = E.analytic_rank(); assert r == ar; Lr1 = E.lseries().dokchitser().derivative(1,r)/r.factorial(); sha = E.sha().an_numerical(); omega = E.period_lattice().omega(); reg = E.regulator(); tam = E.tamagawa_product(); tor = E.torsion_order(); assert r == ar; print("analytic sha: " + str(RR(Lr1) * tor^2 / (omega * reg * tam)))
 
Copy content magma:/* self-contained Magma code snippet for the BSD formula (checks rank, computes analytic sha) */ E := EllipticCurve([0, -1, 0, -8, 112]); r := Rank(E); ar,Lr1 := AnalyticRank(E: Precision := 12); assert r eq ar; sha := MordellWeilShaInformation(E); omega := RealPeriod(E) * (Discriminant(E) gt 0 select 2 else 1); reg := Regulator(E); tam := &*TamagawaNumbers(E); tor := #TorsionSubgroup(E); assert r eq ar; print "analytic sha:", Lr1 * tor^2 / (omega * reg * tam);
 

Modular invariants

Modular form   400.2.a.d

\( q - q^{3} - 2 q^{7} - 2 q^{9} + 3 q^{11} - 4 q^{13} - 3 q^{17} - 5 q^{19} + O(q^{20}) \) Copy content Toggle raw display

Copy content comment:q-expansion of modular form
 
Copy content sage:E.q_eigenform(20)
 
Copy content gp:\\ actual modular form, use for small N [mf,F] = mffromell(E) Ser(mfcoefs(mf,20),q) \\ or just the series Ser(ellan(E,20),q)*q
 
Copy content magma:ModularForm(E);
 

For more coefficients, see the Downloads section to the right.

Modular degree: 48
Copy content comment:Modular degree
 
Copy content sage:E.modular_degree()
 
Copy content gp:ellmoddegree(E)
 
Copy content magma:ModularDegree(E);
 
$ \Gamma_0(N) $-optimal: yes
Manin constant: 1
Copy content comment:Manin constant
 
Copy content magma:ManinConstant(E);
 

Local data at primes of bad reduction

This elliptic curve is not semistable. There are 2 primes $p$ of bad reduction:

$p$ Tamagawa number Kodaira symbol Reduction type Root number $\mathrm{ord}_p(N)$ $\mathrm{ord}_p(\Delta)$ $\mathrm{ord}_p(\mathrm{den}(j))$
$2$ $4$ $I_{5}^{*}$ additive -1 4 13 1
$5$ $3$ $IV$ additive -1 2 4 0

Copy content comment:Local data
 
Copy content sage:E.local_data()
 
Copy content gp:ellglobalred(E)[5]
 
Copy content magma:[LocalInformation(E,p) : p in BadPrimes(E)];
 
Copy content oscar:[(p,tamagawa_number(E,p), kodaira_symbol(E,p), reduction_type(E,p)) for p in bad_primes(E)]
 

Galois representations

The $\ell$-adic Galois representation has maximal image for all primes $\ell$ except those listed in the table below.

prime $\ell$ mod-$\ell$ image $\ell$-adic image
$2$ 2G 8.2.0.1
$3$ 3B 3.4.0.1
$5$ 5B.4.2 5.12.0.2

Copy content comment:Mod p Galois image
 
Copy content sage:rho = E.galois_representation(); [rho.image_type(p) for p in rho.non_surjective()]
 
Copy content magma:[GaloisRepresentation(E,p): p in PrimesUpTo(20)];
 

Copy content comment:Adelic image of Galois representation
 
Copy content sage:gens = [[46, 105, 45, 1], [1, 42, 90, 61], [1, 0, 60, 1], [81, 10, 40, 81], [1, 72, 0, 1], [41, 80, 40, 81], [61, 90, 45, 91], [1, 0, 30, 1], [73, 90, 0, 49], [89, 30, 105, 29], [1, 36, 60, 1]] GL(2,Integers(120)).subgroup(gens)
 
Copy content magma:Gens := [[46, 105, 45, 1], [1, 42, 90, 61], [1, 0, 60, 1], [81, 10, 40, 81], [1, 72, 0, 1], [41, 80, 40, 81], [61, 90, 45, 91], [1, 0, 30, 1], [73, 90, 0, 49], [89, 30, 105, 29], [1, 36, 60, 1]]; sub<GL(2,Integers(120))|Gens>;
 

The image $H:=\rho_E(\Gal(\overline{\Q}/\Q))$ of the adelic Galois representation has level \( 120 = 2^{3} \cdot 3 \cdot 5 \), index $384$, genus $9$, and generators

$\left(\begin{array}{rr} 46 & 105 \\ 45 & 1 \end{array}\right),\left(\begin{array}{rr} 1 & 42 \\ 90 & 61 \end{array}\right),\left(\begin{array}{rr} 1 & 0 \\ 60 & 1 \end{array}\right),\left(\begin{array}{rr} 81 & 10 \\ 40 & 81 \end{array}\right),\left(\begin{array}{rr} 1 & 72 \\ 0 & 1 \end{array}\right),\left(\begin{array}{rr} 41 & 80 \\ 40 & 81 \end{array}\right),\left(\begin{array}{rr} 61 & 90 \\ 45 & 91 \end{array}\right),\left(\begin{array}{rr} 1 & 0 \\ 30 & 1 \end{array}\right),\left(\begin{array}{rr} 73 & 90 \\ 0 & 49 \end{array}\right),\left(\begin{array}{rr} 89 & 30 \\ 105 & 29 \end{array}\right),\left(\begin{array}{rr} 1 & 36 \\ 60 & 1 \end{array}\right)$.

Input positive integer $m$ to see the generators of the reduction of $H$ to $\mathrm{GL}_2(\Z/m\Z)$:

The torsion field $K:=\Q(E[120])$ is a degree-$92160$ Galois extension of $\Q$ with $\Gal(K/\Q)$ isomorphic to the projection of $H$ to $\GL_2(\Z/120\Z)$.

The table below list all primes $\ell$ for which the Serre invariants associated to the mod-$\ell$ Galois representation are exceptional.

$\ell$ Reduction type Serre weight Serre conductor
$2$ additive $4$ \( 25 = 5^{2} \)
$5$ additive $14$ \( 16 = 2^{4} \)

Isogenies

Copy content comment:Isogenies
 
Copy content gp:ellisomat(E)
 

This curve has non-trivial cyclic isogenies of degree $d$ for $d=$ 3, 5 and 15.
Its isogeny class 400c consists of 4 curves linked by isogenies of degrees dividing 15.

Twists

The minimal quadratic twist of this elliptic curve is 50a1, its twist by $-4$.

Growth of torsion in number fields

The number fields $K$ of degree less than 24 such that $E(K)_{\rm tors}$ is strictly larger than $E(\Q)_{\rm tors}$ (which is trivial) are as follows:

$[K:\Q]$ $K$ $E(K)_{\rm tors}$ Base change curve
$2$ \(\Q(\sqrt{-1}) \) \(\Z/3\Z\) 2.0.4.1-1250.3-a3
$3$ 3.1.200.1 \(\Z/2\Z\) not in database
$4$ \(\Q(\zeta_{20})^+\) \(\Z/5\Z\) not in database
$6$ 6.0.320000.1 \(\Z/2\Z \oplus \Z/2\Z\) not in database
$6$ 6.2.4320000.2 \(\Z/3\Z\) not in database
$6$ 6.0.640000.1 \(\Z/6\Z\) not in database
$8$ \(\Q(\zeta_{20})\) \(\Z/15\Z\) not in database
$10$ 10.0.800000000000.1 \(\Z/5\Z\) not in database
$12$ 12.2.52428800000000.2 \(\Z/4\Z\) not in database
$12$ 12.0.18662400000000.1 \(\Z/3\Z \oplus \Z/3\Z\) not in database
$12$ 12.4.51200000000000.2 \(\Z/10\Z\) not in database
$12$ 12.0.6553600000000.1 \(\Z/2\Z \oplus \Z/6\Z\) not in database
$18$ 18.0.396718580736000000000000.1 \(\Z/9\Z\) not in database
$18$ 18.2.82556485632000000000000.1 \(\Z/6\Z\) not in database
$20$ 20.0.640000000000000000000000.1 \(\Z/15\Z\) not in database

We only show fields where the torsion growth is primitive.

Iwasawa invariants

$p$ 2 3 5 7 11 13 17 19 23 29 31 37 41 43 47
Reduction type add ord add ord ord ord ord ord ord ss ord ord ord ord ord
$\lambda$-invariant(s) - 1 - 1 1 1 1 1 1 1,1 3 1 1 1 1
$\mu$-invariant(s) - 0 - 0 0 0 0 0 0 0,0 0 0 0 0 0

An entry - indicates that the invariants are not computed because the reduction is additive.

$p$-adic regulators

Note: $p$-adic regulator data only exists for primes $p\ge 5$ of good ordinary reduction.